Alternating-electric-current-distribution system.



G.'NORTH 'w. s. PEGK. ALTERNAT'ING ELEGTRIG CURRENT DISTRIBUTION SYSTEM.

APPLICATION FILED APE.12, 1909.

Patented 001131, 1011.

ZHSHEETS-SHEET 1.-

WITN ESSES Arno/M W G. NORTH & J. S. PEI/K. ALTERNATING ELECTRIC CURRENTDISTRIBUTION SYSTEM.

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APPLICATION FILED APR. 12, 1909.

UNITED STAT as PigrENtr oFFIoE;

GILBERT NORTH AND JOHN SEDGWICK PECFL, OF MANCHESTER, ENGLAND, ASSIGNORST WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OFPENNSYLVANIA.

ALTERNATING-ELECTRIC-CURRENT-DISTRIBUTION SYSTEM.

To all whom it may concern:

Be it known that We,.GILBER'r NORTH, a subject of the King of GreatBritain, and JOHN SEDGWIUK PEoK, a citizen of the United States, bothresidents of Manchester, in the county of Lancaster, England, haveinvented a new and usefulImprovement in Alternating Electric-CurrentDistribution Systems, of which the followingis a specification.

' Our i 'ention relates. to electric systems of distribution in whichalternating current transformers are employed and it has particularreference to such systems in which both main and auxiliary transformersare interposed between the supply and the distribution systems.

In systems of the above mentioned character the transformers may bearranged in parallel or in series connection across the circuitconductors. \Vith a parallel connection, the main transformer circuitsare arranged to be open at light loads and to be closed only when theload reaches a predetermined value. With a series connection, the mainand auxiliary transformers are connected in series across the circuitconductors and the Windings'of the auxiliary transformer are arranged tobe short-circuited when the load reaches a predetermined value.

' According to the present invention, dis tribution systems of thecharacter referred to above are provided, for the purpose of effectingthe specified connections, with switches which are electro-magneticallyactuated, the circuits of the operating coils of the switches beingcontrolled by means of relays and the switches being so' arranged thatthe circuits which carry any consider-v able currents are, whennecessary, broken through the contacts of the main switches and not atthe relay contacts thus preventing injury to the latter.

The invention 'is illustrated in theaccompanying drawings, of whichFigure 1 is a diagram of connections for a control system'embodying theinvention in which the main and auxiliary transformers are connected inparallel with each other. Fig. 2 is a similar diagram of connections ofa modification of the system shown in Fig. 1. Fig. 3 is a diagram ofconnections for a control system in which the main and auxiliarytransformers are connected in series Specification of Letters Patent.

with each other, Fig. 4 being a similar diagram of connections of amodification of the system hown in Fig. 3. Figs. 5 and 6 show furthe.-modifications of the invention as applied to a three-wire distributionsystem, and Fig. 7 illustrates the type of switch which is preferablyemployed in connection therewith.

Referring now'to Fig. 1, the supply circuit conductors 1-2 are shown asconnected to the distribution circuit conductors 3-4 throughparallel-connected main and auxiliary transformers 5-6, respectively.The primary Winding 9 and the secondary Winding 10 of the auxiliarytransformer 6 are respectively connected across the circuit conductors1-2 and 3-4, while the primary winding 7 and the secondary winding 8 ofthe main transformer 5 are respectively connected to the circuitconductors through an electromagnetically actuated main switch 24 havingstationary contact terminals 11-12 which are respectively connected inthe circuits of the windings 7-8. The main switch 24 also comprises amovable member having two bridge pieces 13-14 which are respectivelyadapted to make contact with the. stationary contact terminals 1112,when the switch is in its closed position.

The operating mechanism of the switch 24 is preferably of the toggletype, as illustrated in Fig. 7, the movable member 15- being raised intoits closed position by means of a closing coil 16, and lowered intoitsopen position by means of an opening coil 17, the circuits of thecoils 16, 17 being controlled by means of a relay 18, comprising a pairof stationary contact terminals 19 connected in the circuit of. theclosing coil Patented Oct. 31, 1911. Application filed April 12, 1909.Serial No. 489,254.

16 and another pair of stationary contact terminals 20 connected in thecircuit of the v opening coil 17. The movable member 22 of the relay 18piece 21 which normally engages the contact terminals 20 of the relay,but is adapted to be moved into engagement with the contact terminals 19when the current through the operating coil 23 of the relay exceeds apredetermined value, the operating coil 23 being connected in circuitwith one of the distribution circuit conductors 3. It will be seen thatthe closing coil 16 of the main switch 24 is connected across thecontact terminals 12 in series with the contact terminals 19 is providedwith a bridge f of the relay 18, while the opening coil 17 is connectedbetween one of the contact terminals 12 of the switch 24 and thedistribution circuit conductor 3 through the contact terminals 20 of therelay 18.

The operation of the apparatus is as follows :Assuming the main switch24 and the relay 18 to be in the positions indicated in the drawing, thedistribution circuit condurtors 3 4 will. be supplied with (.HGIgthrough the auxiliary transfi)ruier (3, the

.primary and secondary circuits 1 8 respectively of the main transformer5 being broken at the contact terminals 11--12 of the main switch. Ifthe load upon the distribution circuit be increased beyond thepredetermined value at which the energizing coil 23 of the relay 18 isdesigned to operate, the movable men'iber 22 of the relay 18 will beraised so that its bridge piece 21. engages the relay contact terminal,19. A circuit will. thus be completed from the circuit conductor 3through the main transformer winding 8, one contact terminal 12 of theswitch 24, the closing coil 16, the contact terminals 19 and the bridgepiece 21 of the relay 18 and the other contact terminal 12 to the othercircuit conductor 4. The closing coil 16 of the switch 24- being thusenergized, the movable member 15 of the switch will be moved into itsclosed position and the bridge pieces 13 and 14 will connect the primaryand secondary windings 78 of the main transformer 5 to the supply and Ithe distribution circuit conductors, respec tively. The engagement ofthe bridge piece 14 of the main switch with the stationary contactterminals 12 will short-circuit the closing coil 16 which is, therefore,energized only during the actual movement of the switch into its closedposition. If the load on the distribution circuit conductors decreasesbelow the predetermined value, the movable member 22 of the relay 18will resume its former position, and the bridge piece 21 will engage thecontact terminals 20, thus completing a circuit from the circuitconductor 4 through the contact terminals 12, the bridge piece 14, theopening coil 17 and the contact terminals 20 of relay 18 to the othercircuit conductor 8. The switch 24 will,'consequently, move to its openposition in, which the circuit of the opening coil 17 is broken by theseparation of the bridge piece 14 from the contact terminals 12.

It will be seenfrom the above description that the circuits of theopening and closing coils 16'-17 of the main switch 24 are broken at themain contacts 1112, the contacts 1920 of the relay 18 being merelyrequired to complete the circuits of the opening and closing coils.

In some cases it may be found that the connections above describedprovide insufficient current to operate the closmg coil 16 of the switch24, since the coil is traversed only by the magnetizing current takenby.

the main transformer winding 8, when the latter is unloaded. In suchcases, the moditrated in which the main and auxiliary transformers 56are connected in series with each other between the circuit conductors1--2, and 3 4, the primary and secondary windings 9-10 of the auxiliarytransfo mer (3 being arranged to be short-circuited by means of theelectro-magnetically operated switch 24 when the load on the circuitconductors 34 exceeds a predetermined value. The opening coil 17 of theswitch 24 is connected between the bridge. piece 14 of the switch andthe circuit conductor 3, through the contact terminals 20 of the relay18, the closing coil 16 being connected across the contact terminals 12of the switch 24 through the relay contact terminals 19, as in thesystem of Fig. 1. The circuit of the opening coil 17 is thus broken atthe bridge piece 14 and the contact terminals 12 of the switch 24, whilethe closing coil 16 is shortcircuited by the bridge piece 14 when theswitch is in its closed position.

Referring now to Fig. 4, a modification, similar to that illustrated inFig. 2 is illustrated in which the circuit of the closing coil 1.6 isarranged to be broken at the contact terminals of a special switch 25,which is open when the switch 24 is in its closed position, thisarrangement being intended to be used for systems in which thearrangement to How through the closing coil 16, by reason of itsconnection in series with the main transformer winding 8.

Referring now to Fig. 5, in which the invention is illustrated asapplied to a threewire distribution system having the main and auxiliarytransformers connected in parallel with each other, the connections areseen to be very similar to those of Fig. 1 except that the switch 24 isprovided wit-h an additional bridge piece 26 which when the switch isclosed, connects the middle point of the main transformer secondarywinding to the neutral or balancing conductor 27 of the distributionsystem.

Fig. 6 illustrates the invention as applied to a three-Wire distributionsystem in which connected in series with each other, the

110 of Fig. 3 would not allow suificient current I bridge piece 26 ofthe switch 24 being connected to the neutral or balancing conductor ofthe distribution system, and the closure of the switch serving toshort-circuit the secondary winding of the auxiliary transformer.

It will be noted that the primary winding of the main transformercomprises two portions 28 and 29, between which the primary winding 30of the auxiliary transformer is connected when the'switch 242' is open.It will also be noted that the-secondary winding of the main transformercomprises two portions 28 and 29 between which is connected thesecondary windingBO of the auxiliary transfornnr and that the commonterminals of the three windings are connected to the stationary contactterminals of the switch 24 that are engaged by the member 26 when theswitch is 'closcd. hen the switch 24 is open, the middle point of theseries-connected secondary windings is connected. to the neutralconductor 27 by the conductor 31 and when the switch is closed the windisnort circuited and the adjacent tenainals of the windings 28 and 2t areconnected together by the'switch and to the neutral conductor 27 by theconductor 26*.

The invention, which is applicable to single or polyphase distributionsystems, is evidently capable of wide variation, as regards the mannerof carrying out the same, and is not to be regarded as limited, exceptby the restrictions imposed by the state of the art.

We claim as our invention:

1. In an alternating current. distribution system, main and auxiliarytransformers, a

switch forcontrolling the connection of one.

of the transformers, a relay comprising contact terminals for governlngthe operation of the switch, C1ICl11tS.Wl1lCh include contact terminalsof the switch and a single .system, main and auxiliary transformersconnected between the supply and distribution circuits, a switch forcontrolling the connections of one of said transformers, an opening coiland a closing coil for said switch, a relay comprising contact terminalsfor making and breaking the circuit connections of said coils, relaycircuits which include the contact terminals of the switch and a singleactuating coil in the main distributing circuit.

4. In an alternating current distribution system, main and auxiliarytransformers connected between the supply and distribution circuits, anelectro-magnetically oper- 'ated switch for controlling the connectionsof one of thetransformers, opening and closing coils for directlyactuating the switch and a relay for connecting the opening and closingcoils to the circuit conductors through contact terminals of the switch,said relay having a single actuating coil in the main distributingcircuit.

5. In an alternating current distribution system, main 4 and auxiliarytransformers connected between the supply and distribution circuits, anelectro-magnetically operated switch for controlling the connections ofone of thetransformers, opening and closing coils for the switch, and arelay for one of the coils being opened at the contact terminals of themain switch.

6. Inan alternating current distribution system; main and auxiliarytransformers connected between the supply and distribution circuits, aswitch for controlling the connections of one of the transformers,opening and closing coils for a switch, and a relay for closing thecircuits of both coils, the circuit of one of the coils being opened andthe other coil being short-circuited at the contact terminals of theswitch.

7 In an alternating current distribution system, main and auxiliarytransformers connected between the supply and distribution circuits, aswitch for controlling the connections of one of the transformers, aclosing coil for said switch, relay contactterminals interposed betweensaid closing coil and the contact terminals of said switch, an openingcoil for the switch and relay contact terminals interposed between saidopening coil and the distribution circuit conductors.

8. In an alternating current, distribution system, main and auxiliarytransformers connected to the supply and distribution circuits, a switchfor controlling the connections of one of the transformers, a closing.coil for said switch, relay contact terminals interposed between saidclosing coil and the contact terminals of the main switch, an openingcoil for the switch, and relay contact terminals interposed between saidopening coil and the distribution circuit conductors and-connected tocontact terminals of the main switch.

""9. In an alternating currentdistribution for opening and closing ashort-circuit conclosing the circuits of both of said coils,

nection across the terminals of the auxiliary transformer, and a relayfor governing the one of the relay circuits including the .con

tact terminals of the switch.

11. In an alternating current distribution system, main and auxiliarytransformers connected between the supply and distribution circuits, anelectro-magnctically operated switch for controlling the connections ofone of the transformers, a; relay, an opening coil for the switchconnected through relay contact terminals and through the switchcontactterminals to the'distribution circuit conductors, a closing coilfor the switch and means for connecting the opening coil through relaycontact terminals to the distribution circuit only when the switch is inclosed position.

12. In an alternating current distribution system, main and auxiliarytransformers, an electro-magnetically operated switch for controllingthe connections of one of the trans formers, an opening coil for theswitch con nected between the movable member of the switch and one ofthe contact terminals of the distribution circuit and a closing coil forthe switch.

13. In an alternating current distribution system, main and auxiliarytransformers connected to a three-wire distributing circuit, a switchfor controlling the connections of one of the transformers, a relay forgoverning the operation of the switch, antrelay circuits including thecontact terminals of the switch.

14:. in an alternatingcurrent diiti'ibution system, main and auxiliarytransformers connected between the supply and distribution circuits, anelectro-magnetically operated toggle switch for controlling the connections of one of the transformers, opening and closing coils foroperating the switch and a single relay for connecting the opening andclosing coils to the distribution circuit conductors tl'irough thecontact terminals of the switch.

In testimony whereof we have hereunto subscribed our names this Q-lthday of March, 1909.

Gll llllllt'l. NORTH. JOHN SEDGOVICK PECK. lvitness cs G. lV. PINNAR, J.Memos.

